a guy over at a5og clamped a barrelfront onto the flatline and said it would be more accurate with that.

find it at the bottom here Show off your Sniper A-5!!! - Page 8

A5og has a thread on tunning your flatline. basicaly make shure its clean and start your fps low and work your way up until it just starts to have flatline affect. raise fps slowly until it becomes less accurate and then back down. They all seem to behave different @ fps 245 - 275 seems to be norm. I had mine on a phenom and the tricks help allot.